Motor assembly for driving a pump or rotary device having a cooling duct

ABSTRACT

A motor assembly for driving a pump (e.g., liquid pump) includes an electric motor with an output shaft. A motor frame houses the electric motor so that the output shaft protrudes from an end of the motor frame. A plate assembly is coupleable about the output shaft to the end of the motor frame. The please assembly has a cavity that houses motor drive electronics. The plate assembly further defines a duct that extends between a central opening and one or more openings on an outer radial wall of the plate assembly. A fan is coupled to the output shaft so that the plate assembly is disposed between the fan and the motor frame. Rotation of the output shaft by the electric motor rotates the fan, causing air to flow through the duct. Air flow through the duct inhibits heat transfer between the electric motor and the motor drive electronics.

BACKGROUND Field

This invention relates broadly to an electric motor assembly for drivinga pump, and more particularly to an electric motor assembly having acooling duct that provides improved thermal isolation of the electricmotor from drive electronics of the electric motor assembly.

Description of the Related Art

Industrial pumps are used to pump fluids, such as chemicals, in anindustrial setting (e.g., a chemical manufacturing plant). Such pumpsinclude an electric motor to drive the pump (e.g., drive the rotation ofthe pump impeller) and electronics to power and/or control the operationof the electric motor. Operation of the electric motor generates heat.

SUMMARY

It is an object of this disclosure to provide an electric motor assembly(e.g., for use with industrial pumps) that has improved heat dissipationto reduce the exposure of the electronics of the assembly to heatgenerated by the electric motor.

In accordance of with one aspect of the disclosure, a plate assembly foruse with an electric motor assembly (e.g., that can be used withindustrial pumps) has a cooling duct through which air flows todissipate heat generated by the electric motor and reduce the exposureof the electronics in the plate assembly to heat from the electric motor(e.g., the cooling duct provides a thermal barrier). In one example,such a cooling duct can aid in reducing a temperature the electronicsare exposed to as compared to a similar electric motor assembly usingtypical insulation material between the electronics and the electricmotor.

In accordance with another aspect of the disclosure, an electric motorassembly for driving a pump is provided. The assembly comprises anelectric motor having an output shaft that extends along a central axisof the electric motor, the electric motor being operable to rotate theoutput shaft. A motor frame houses the electric motor so that the outputshaft protrudes from an end of the motor frame. A plate assembly havinga central opening is configured to receive the output shafttherethrough. The plate assembly is coupleable about the output shaftproximate to the end of the motor frame. The plate assembly defines achamber configured to house motor drive electronics. The plate assemblyfurther defines a duct that extends between the central opening and oneor more openings on an outer radial wall of the plate assembly, so thatthe duct is at least partially disposed between the electric motor andthe motor drive electronics. A fan is coupleable to the output shaft sothat the plate assembly is disposed between the fan and the motor frame.Operation of the electric motor rotates the output shaft to rotate thefan. Rotation of the fan causes air to flow through the duct and to exitout of said one or more openings. Air flow through the duct inhibitsheat transfer between the electric motor and the motor drive electronics(e.g., air flow through the duct at least partially thermally isolatesthe motor drive electronics from heat generated by the electric motor).

In accordance with another aspect of the disclosure, a plate assembly isprovided configured for use with an electric motor assembly for drivinga pump. The electric motor assembly can have an electric motor with anoutput shaft, a motor frame that houses the electric motor and a fanrotatably coupleable to the output shaft. The plate assembly comprises acentral opening configured to receive the output shaft therethrough, theplate assembly coupleable about the output shaft proximate to an end ofthe motor frame and defining a chamber that houses motor driveelectronics. The plate assembly also comprises a duct that extendsbetween the central opening and one or more openings on an outer radialwall of the plate assembly, the duct configured to be at least partiallydisposed between the electric motor and the motor drive electronics.Operation of the fan causes air to flow through the duct and to exit outof said one or more openings. Air flow through the duct inhibits heattransfer between the electric motor and the motor drive electronics(e.g., air flow through the duct at least partially thermally isolatesthe motor drive electronics from heat generated by the electric motor).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an exploded view of an electric motor assembly for driving apump or rotary device.

FIG. 1B is a partially assembled view of the electric motor assembly ofFIG. 1A, excluding the fan and shroud cover.

FIG. 2A is a cross-sectional view of the electric motor assembly.

FIG. 2B is an enlarged partial view of the motor assembly in FIG. 2A.

FIG. 3 is partial side view of the motor assembly of FIG. 2A.

FIG. 4 is partial perspective view of a plate assembly of a motorassembly for driving a pump or rotary device, in accordance with anotherexample.

FIG. 5 is a schematic cross-sectional view of the plate assembly in FIG.4 showing an air velocity flow diagram through the flow path duringoperation of the motor assembly.

FIG. 6 is a schematic cross-sectional view of the plate assembly in FIG.4 showing a temperature contour diagram during operation of the motorassembly.

FIG. 7 is a perspective view of the mid-plate of the motor assembly.

FIG. 8 is an exploded view of an end-plate assembly of the motorassembly and the drive module electronics therein.

FIG. 9 is a partial view of a motor side of the end-plate assembly ofFIG. 8 .

FIG. 10 is a rear view of a power plane printed circuit board layerhoused in the end-plate assembly of FIG. 8 .

FIG. 11 shows an assembled matrix converted in the end-plate assembly ofFIG. 8 .

DETAILED DESCRIPTION

FIGS. 1A-2A show an example motor assembly 1000. The motor assembly 1000can optionally be coupled to a pump (not shown) to drive the pump. Themotor assembly 1000 includes an electric motor 100 with an output shaftor rotor 120. The motor 100 can be housed in a motor frame 200 so that afirst end of the output shaft or rotor 120 protrudes from an end 210 ofthe motor frame 200. As shown, a second end of the output shaft or rotor120 protrudes from the other end of the motor frame 210, and may becoupled to the pump. The motor assembly 1000 can include a plateassembly P removably coupleable over the output shaft or rotor 120 tothe motor frame 200. The plate assembly P can optionally include one orboth of a mid-plate 300 and an end-plate 400. The plate assembly Poptionally includes a bearing 140 via which it couples to the outputshaft or rotor 120.

The mid-plate 300 can couple to the output shaft or rotor 120 via thebearing 140, which can be disposed in an opening 320 (e.g., bearinghousing or sleeve) of the mid-plate 300 (see, e.g., FIGS. 2B and 7 ).The mid-plate 300 can be disposed adjacent the end 210 of the motorframe 200 and has a recess or cavity 340 that faces the motor frame 200.The mid-plate 300 can have one or more (e.g., a plurality of) heat sinkfins 310 extending from an outer surface (e.g., outer peripheralsurface) of the mid-plate 300 to facilitate heat dissipation.

The end-plate 400 can coupled to the mid-plate 300 so that the mid-plate300 is interposed between the end 210 of the motor frame 200 and theend-plate 400. The output shaft or rotor 120 extends through an opening410 in the end-plate 400. The end-plate 400 can have a cavity 420,defined at least in part by an end wall 460, that receives an electronicmodule 700 therein, which is further discussed below.

A fan 500 couples to the output shaft or rotor 120 so that the end-plate400 is interposed between the fan 500 and the mid-plate 300. The fan 500is rotatably coupled to the output shaft or rotor 120 such that rotationof the output shaft or rotor 120 rotates the fan 500.

A shroud cover 600 can be removably disposed over the mid-plate 300,end-plate 400 and fan 500. The shroud cover 600 can removably attach(e.g., with one or more fasteners, such as screws or bolts) to the motorframe 200.

The motor assembly 1000 can further include a terminal box 600 attachedto the motor frame 200. The terminal box 600 has connector wires 610that can extend into channels 430 of a terminal box connector 440 (seeFIG. 8 ) of the end-plate 400 to electrically connect electronics in theterminal box 600 with electronic module 700 (see FIG. 8 ) in theend-plate 400. The mid-plate 300 and end-plate 400 can be made ofcopper, aluminum or cast iron.

FIGS. 2A-2B show a cross-sectional view of the motor assembly 1000. FIG.3 shows a partial assembled side view of the motor assembly 1000.

The electric motor 100 includes a stator 110 disposed about the outputshaft or rotor 120. A plate assembly P can detachably couple to the end210 of the motor frame 200. Optionally, the plate assembly P can includea mid-plate 300 and an end-plate 400. In another implementation,discussed further below, the plate assembly P can instead include asingle (e.g., integral, monolithic, single piece) plate. The plateassembly P optionally includes the bearing 140 via which it couples tothe output shaft or rotor 120.

The mid-plate 300 is disposed proximate (e.g., adjacent) the end 210 ofthe motor frame 200, the end-plate 400 is disposed proximate (e.g.,adjacent) the mid-plate 300 so that the mid-plate 300 is interposedbetween the motor frame 200 and the end-plate 400, and the fan 500 isdisposed proximate (e.g.,) the end-plate 400 so that the end-plate 400is interposed between the mid-plate 300 and the fan 500. The end-plate400 has a cavity 420 that can house an electronic module (e.g., theelectronic module 700). The fan 500 is rotatably coupled to the outputshaft or rotor 120 via a mechanical connection 510 (e.g., spline, gearedconnection), so that rotation of the rotor 120 rotates the fan 500.

With continued reference to FIGS. 2A-3 , the plate assembly P (e.g., oneor both of the end-plate 400 and mid-plate 300) defines a flow path Fthrough which air flow generated by the fan 500 flows. The flow path Fcan be defined at least in part by a channel 550 (e.g., annular channel)between the output shaft or rotor 120 and a wall (e.g., inner radialwall) 422 of the plate assembly P (e.g., of the end-plate 400). Thechannel 550 can extend generally parallel to at least a portion of theoutput shaft or rotor 120 (e.g., extend coaxially with the output shaftor rotor 120, extend along an axis parallel to an axis of the outputshaft or rotor 120).

The flow path F can be defined at least in part by a duct or channel 555defined in the plate assembly P (e.g., defined at least partiallybetween a first wall 556 and a second wall 558 that are spaced apartfrom each other to define the open duct). At least a portion of the ofthe first and second walls 556, 558 can extend generally transversely(e.g., perpendicular) to the output shaft or rotor 120. The duct orchannel 555 is in fluid communication (at an upstream end of the channel555) with the channel 500 such that air flow passes through the channel550 from the fan 500 and into the duct or channel 555 from the channel550. The duct or channel 555 is in fluid communication (at a downstreamend of the channel 555) with one or more openings 560 of the plateassembly P via which air flow exits the plate assembly P. One or both ofthe channel 550 and duct 555 define a cooling duct that can thermallyisolate the electronic module in the cavity 420 from the electric motor100 and motor frame 200, as further discussed below.

In one implementation, the duct or channel 555 includes one or more(e.g., a plurality of) separate ducts extending between the channel 550and the one or more openings 560 (e.g., multiple ducts circumferentiallydistributed about a central axis X of the plate assembly P). In anotherimplementation, the duct or channel 555 extends circumferentially aboutthe central axis X such that air flows alongside substantially anentirely of the first and second walls 556, 558 circumferentially aboutthe central axis X (e.g., the channel or duct 555 is defined by rotatingthe image in FIG. 2B about the central axis X).

In the illustrated implementation, the plate assembly P includes themid-plate 300 and end-plate 400 that removably couple to each other. Thechannel 550 is defined in the end-plate 400 by the inner radial wall422. The duct or channel 555 is defined in the mid-plate 300 between thewalls 556, 558 of the mid-plate 300.

As best shown in FIG. 2B, the end-plate 400 has an outer radial wall 450that extends from a shoulder 455 of the end-plate 400. The mid-plate 300has an outer radial wall 350 that extends from a first end 351 to asecond end 352, and heat sink fins 310 that extend from the outer radialwall 350. The outer radial wall 350 extends over the outer radial wall450 of the end-plate 400 (e.g., the outer radial wall 450 is disposedradially inward of the outer radial wall 350) so that the first end 351is proximate (e.g., adjacent) the shoulder 455. The second end 352 isdisposed proximate (e.g., adjacent) the end 210 of the motor frame 200and has a lip 354 that extends into a recessed portion of the motorframe 200 and adjacent an inner surface 215 of the motor frame 200.

The mid-plate 300 has a cavity or recess 340 that faces the end 210 ofthe motor frame 200 and is defined at least in part by the outer radialwall 350, a wall 342 that extends generally parallel to at least aportion of the wall 558, and an inner radial wall 355 that defines thecentral opening 320 of the mid-plate 300. The bearing 140 is disposedbetween the output shaft or rotor 120 and the inner radial wall 355.

In operation, the electric motor 100 can be operated to rotate theoutput shaft or rotor 120, which in turn rotates the fan 500 to generateair flow. Air flows from the fan 500 through the flow path F, first(axially) through the channel 550 and then (at least partially in aradial direction) through the duct or channel 555. Said air flow exitsthe plate assembly P via the one or more (e.g. plurality of) openings560 of the plate assembly P (e.g., of the mid-plate 300). Such air flowalong the flow path F to advantageously thermally insulate (e.g.,thermally isolate) the cavity or chamber 420, and the electronics (e.g.,electronic module 700) therein, from the heat generated by the motor100, thereby inhibiting damage to said electronics from such heat.

FIGS. 4-6 shows a partial perspective view of a plate assembly P′ foruse in an electric motor assembly, such as the electric motor assembly100. The plate assembly P′ is similar to the plate assembly P in FIGS.2A-3 . Thus, reference numerals used to designate the various componentsof the plate assembly P′ are similar to those used for identifying thecorresponding components of the plate assembly P in FIGS. 2A-3 , exceptthat an “B” has been added to the numerical identifier. Therefore, thestructure and description for the various features of the plate assemblyP in FIGS. 2A-3 are understood to also apply to the correspondingfeatures of the plate assembly P′ in FIGS. 4-6 , except as describedbelow.

The plate assembly P′ differs from the plate assembly P in FIGS. 2A-3 inthat the plate assembly P′ is a single piece (e.g., does not include aseparate mid-plate 300 and end-plate 400). The plate assembly P′ canhave a cavity or chamber 420B defined between an end wall 460B and afirst wall 556B that extend generally transverse to a central axis X′ ofthe plate assembly P′. The cavity or chamber 420B can house anelectronic module 700B therein.

The plate assembly P′ includes a flow path F′ through which air can flow(e.g., when the fan, such as fan 500, coupled to the output shaft orrotor 120 is rotated). The flow path F′ is defined at least in part by achannel 550B (e.g., annular channel) that extends between a central axisX′ of the plate assembly P′(e.g., between the output shaft or rotor whenthe plate assembly P′ is coupled to it) and a wall (e.g., inner radialwall) 422B of the plate assembly P′. The channel 550B can extendgenerally parallel to at least a portion of the central axis X′ (e.g.,extend coaxially with the central axis X′, extend along an axis parallelto the central axis X′, extend coaxially with or parallel to the outputshaft or rotor when the plate assembly P′ is coupled to it).

The flow path F′ can be defined at least in part by a duct or channel555B defined in the plate assembly P′ (e.g., defined at least partiallybetween the first wall 556B and a second wall 558B that are spaced apartfrom each other to define the open duct). At least a portion of the ofthe first and second walls 556B, 558B can extend generally transversely(e.g., perpendicular) to the central axis X′ (e.g., to the output shaftor rotor when the plate assembly P′ is coupled to it). The duct orchannel 555B is in fluid communication (at an upstream end of thechannel 555B) with the channel 500B such that air flow passes throughthe channel 550B (due to operation of the fan 500) and into the duct orchannel 555B from the channel 550B. The duct or channel 555B is in fluidcommunication (at a downstream end of the channel 555B) with one or moreopenings 560B of the plate assembly P′ via which air flow exits theplate assembly P′. One or both of the channel 550B and duct 555B definea cooling duct that can thermally isolate the electronic module in thecavity 420B from the electric motor 100 and motor frame 200, as furtherdiscussed below.

In one implementation, the duct or channel 555B includes one or more(e.g., a plurality of) separate ducts extending between the channel 550Band the one or more openings 560B (e.g., multiple ductscircumferentially distributed about a central axis X′ of the plateassembly P′). In another implementation, the duct or channel 555Bextends circumferentially about the central axis X′ such that air flowsalongside substantially an entirely of the first and second walls 556B,558B circumferentially about the central axis X′ (e.g., the channel orduct 555B is defined by rotating the image in FIG. 4 about the centralaxis X′).

In operation, the electric motor 100 can be operated to rotate theoutput shaft or rotor 120, which in turn rotates the fan 500 to generateair flow. Air flows from the fan 500 through the flow path F′, first(axially) through the channel 550B and then (at least partially in aradial direction) through the duct or channel 555B. Said air flow exitsthe plate assembly P′ via the one or more (e.g. plurality of) openings560B of the plate assembly P′. Such air flow along the flow path F′ toadvantageously thermally insulate (e.g., thermally isolate) the cavityor chamber 420B, and the electronics (e.g., electronic module 700B)therein, from the heat generated by the motor 100, thereby inhibitingdamage to said electronics from such heat.

FIG. 5 shows a schematic cross-sectional view of the plate assembly P′in FIG. 4 , showing an air velocity flow diagram through the flow pathF′, for example, during operation of the fan 500.

FIG. 6 shows a schematic cross-sectional view of the plate assembly P′in FIG. 4 showing a temperature contour diagram of the plate assembly P′during operation of the fan 500 to cause air flow to flow through theflow path F′. The temperature contour diagram shows that the chamber420B remains relatively cool while the second wall 558B increases intemperature. Testing of the plate assembly P, P′ with the cooling ductand air flow path F, F′ as compared to a plate assembly that insteadused an insulation material resulted in a reduction in the temperatureincrease the chamber 420B was exposed to from the motor 100, as well asa reduction in the temperature the power module in the plate assembly P,P′ was exposed to, as shown in table 1 below.

TABLE 1 Temperature comparison of Plate Assembly Thermal InsulationMaximum Power Chamber Average Plate Assembly Module TemperatureTemperature Rise Insulation Rise (K) (K) Insulation Material 93.2 76.3Cooling Duct 90   66.7

FIG. 7 shows a power plane side of the mid-plate 300 (e.g., a side ofthe mid-plate 300 that faces toward the end-plate 400). The mid-plate300 can have a wall 556 that faces the end-plate 400 when the electricmotor assembly 1000 is assembled. The mid-plate 300 can have one or more(e.g., multiple) fastener holes 360 that can optionally receivefasteners (e.g., bolts) to couple the mid-plate 300 to the end-plate400.

FIG. 8 shows an exploded view of a drive module assembly 800 of theelectric motor assembly 1000. The drive module assembly 800 includes theend-plate 400 with the cavity or chamber 420 defined at least in part bythe end wall 460 and circumferential outer wall 450. The end-plate 400also has a hub 465 that defines the opening 410 at the center of theend-plate 400, and also includes the terminal box connector 440 with thechannels 430 that receive the connector wires 610 of the terminal box600. A connector cover 445 can be attached to the terminal box connector440 with one or more fasteners 447 (e.g., screws, bolts). The drivemodule assembly 800 also includes the electronics module 700, discussedfurther below, which can be housed in the chamber 420. The chamber 420has a generally circular shape and receives a similarly shapedelectronic module 700 therein. Once the electronic module 700 is in thechamber 420, the chamber 420 can be covered with one or both of anend-plate cover gasket or insulator 810 and an end-plate cover 820optionally using one or more fasteners (e.g., bolts, screws) 830.

FIGS. 9-11 show features of the electronic module 700. The electronicmodule 700 can provide power and control functionality to operate theelectric motor assembly 1000 in order to drive the pump or other rotarydevice coupled to the electric motor assembly 1000. The electronicmodule 700 can have a printed circuit board or power plane assembly 710with a circular shape (e.g., annular shape with a central opening 711).The electronic module 700 can be disposed in the chamber 420 of theend-plate 400 so that the central opening 711 is disposed about the hub465 and an outer edge 701 of the printed circuit board or power planeassembly 710 is disposed inward of the circumferential outer wall 450 ofthe end-plate 400. Accordingly, the electronics can be arrangedcircumferentially about the hub 465 on the printed circuit board orpower plane assembly 710 so that the power and control electronics arehoused in the chamber 420 of the end-plate 400.

The printed circuit board or power plane assembly 710 can optionally bea multi-layer circuit board or assembly, and can be constructed of alaminated material, such as fiberglass, which can advantageouslyinsulate the hotter power semi-conductors from more temperaturesensitive control electronics and power quality capacitors. For example,the printed circuit board or power plane assembly 710 can have a powerlayer, a control layer, a thermal barrier and a printed circuit boardlayer.

The power layer can include one or more higher temperature power modules(PM1-PM9) 718 operable to provide power to the electric motor 100. Thecontrol layer can include lower temperature control electronics modules,such as one or more power quality or input filter capacitors (IFC) 703for controlling the power provided to the electric motor 100. The powermodules (PM1-PM9) 718 can be on an opposite side of the printed circuitboard or power plane assembly 710 (e.g., on opposite sides of thethermal barrier) from the power quality or input filter capacitors (IFC)703. The thermal barrier and printed circuit board layer can be betweenthe power layer and the control layer and provide electrical connectionpaths between the power modules 718 of the power plane and the controlelectronics modules (e.g., power quality or input filter capacitors 703)of the control layer, allowing the interconnection of these components.The printed circuit board or power plane assembly 710 alsoadvantageously provides thermal insulation between the power layer andthe control layer. The printed circuit board or power plane assembly 710advantageously insulates and/or directs heat emitted from one or more ofthe power modules 718, the control electronics modules such as the inputfilter capacitors (IFC) 703 and output shaft or rotor 120 of theelectric motor 100 to the outer edge 701 of the printed circuit board orpower plane assembly 710 where higher air flow from the fan 500 isdirected.

With reference to FIG. 9 , the electronic module 700 can include, inaddition to one or more (e.g., a plurality of) power quality or inputfilter capacitors (IFC) 703, a controller 702, a main power supply 704,a gate drive layer 706 and one or more clamp capacitors 708 on one sideof the printed circuit board or power plane assembly 710. With referenceto FIG. 10 , the opposite side of the printed circuit board or powerplane assembly 710 can include, in addition to the power modules 718,one or more output clamp diode connections 712, a clamp insulated-gatebipolar transistor (IGBT) connection 714, one or more shunt resistorconnections 716, and one or more input filter capacitor (IFC)connections 720.

FIG. 11 shows a an assembled electronic module 700 arranged in thechamber 420 of the end-plate 400. The electronic module 700 includes oneor more input filter capacitors 703, a gate driver power supply 728, oneor more controller cards 740, one or more clamp capacitors 730, 732, 734and a clamp control circuit 738, and a copper connection 736. Theelectronic module 700 can include a matrix converter to convert amulti-phase AC input of fixed voltage and frequency into a multi-phaseAC output waveform of a desired frequency and phase. Therefore, thematrix converter is able to synthesize AC output waveforms of desiredfrequency and phase relative to the input AC waveforms. Since the rateat which electric motors, such as the electric motor 100 rotates isbased on the frequency of the applied AC input signal, using a matrixconverter to power the electric motor 100 allows for variable drivecontrol. For example, the frequency of the AC output waveform providedby the matrix converter can be changed over time to thereby operate theelectric motor 100 at the desired speed. The electronic module 700provides an embedded motor drive (EMD) that operates similar to avariable frequency drive (VFD) and that controls the input frequency andvoltage to the electric motor 100 to allow more precise speed controlfor the electric motor 100 (e.g., allowing the motor 100 to run atspeeds higher than the input line frequency). The embedded motor drive(EMD) advantageously provides for improved reliability, increasedthroughput and reduced energy consumption for the electric motorassembly 1000.

The circular shape of the electronic module 700 advantageously allows itto fit within the chamber 420 of the end-plate 400, allowing ease ofmanufacture and installation of its components. As the end-plate 400 canbe detached from the motor frame 200, maintenance of the electronicmodule 700 (e.g., to replace one or more components, such as a faulty ordamaged transistor) is simplified. Additionally, the circular shape ofthe electronic module 700 allows existing electric motor assemblies tobe retrofitted with the electronic module 700 to provide such anassembly with the embedded motor drive or variable frequency driveprovided by the electronic module 700 (e.g., by installing theelectronic module 700 in the standard sized end-plate of the electricmotor assembly).

While certain embodiments of the inventions have been described, theseembodiments have been presented by way of example only, and are notintended to limit the scope of the disclosure. Indeed, the novel methodsand systems described herein may be embodied in a variety of otherforms. Furthermore, various omissions, substitutions and changes in thesystems and methods described herein may be made without departing fromthe spirit of the disclosure. The accompanying claims and theirequivalents are intended to cover such forms or modifications as wouldfall within the scope and spirit of the disclosure. Accordingly, thescope of the present inventions is defined only by reference to theappended claims.

Features, materials, characteristics, or groups described in conjunctionwith a particular aspect, embodiment, or example are to be understood tobe applicable to any other aspect, embodiment or example described inthis section or elsewhere in this specification unless incompatibletherewith. All of the features disclosed in this specification(including any accompanying claims, abstract and drawings), and/or allof the steps of any method or process so disclosed, may be combined inany combination, except combinations where at least some of suchfeatures and/or steps are mutually exclusive. The protection is notrestricted to the details of any foregoing embodiments. The protectionextends to any novel one, or any novel combination, of the featuresdisclosed in this specification (including any accompanying claims,abstract and drawings), or to any novel one, or any novel combination,of the steps of any method or process so disclosed.

Furthermore, certain features that are described in this disclosure inthe context of separate implementations can also be implemented incombination in a single implementation. Conversely, various featuresthat are described in the context of a single implementation can also beimplemented in multiple implementations separately or in any suitablesubcombination. Moreover, although features may be described above asacting in certain combinations, one or more features from a claimedcombination can, in some cases, be excised from the combination, and thecombination may be claimed as a subcombination or variation of a subcombination.

Moreover, while operations may be depicted in the drawings or describedin the specification in a particular order, such operations need not beperformed in the particular order shown or in sequential order, or thatall operations be performed, to achieve desirable results. Otheroperations that are not depicted or described can be incorporated in theexample methods and processes. For example, one or more additionaloperations can be performed before, after, simultaneously, or betweenany of the described operations. Further, the operations may berearranged or reordered in other implementations. Those skilled in theart will appreciate that in some embodiments, the actual steps taken inthe processes illustrated and/or disclosed may differ from those shownin the figures. Depending on the embodiment, certain of the stepsdescribed above may be removed, others may be added. Furthermore, thefeatures and attributes of the specific embodiments disclosed above maybe combined in different ways to form additional embodiments, all ofwhich fall within the scope of the present disclosure. Also, theseparation of various system components in the implementations describedabove should not be understood as requiring such separation in allimplementations, and it should be understood that the describedcomponents and systems can generally be integrated together in a singleproduct or packaged into multiple products.

For purposes of this disclosure, certain aspects, advantages, and novelfeatures are described herein. Not necessarily all such advantages maybe achieved in accordance with any particular embodiment. Thus, forexample, those skilled in the art will recognize that the disclosure maybe embodied or carried out in a manner that achieves one advantage or agroup of advantages as taught herein without necessarily achieving otheradvantages as may be taught or suggested herein.

Conditional language, such as “can,” “could,” “might,” or “may,” unlessspecifically stated otherwise, or otherwise understood within thecontext as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements, and/or steps. Thus, such conditional language is notgenerally intended to imply that features, elements, and/or steps are inany way required for one or more embodiments or that one or moreembodiments necessarily include logic for deciding, with or without userinput or prompting, whether these features, elements, and/or steps areincluded or are to be performed in any particular embodiment.

Conjunctive language such as the phrase “at least one of X, Y, and Z,”unless specifically stated otherwise, is otherwise understood with thecontext as used in general to convey that an item, term, etc. may beeither X, Y, or Z. Thus, such conjunctive language is not generallyintended to imply that certain embodiments require the presence of atleast one of X, at least one of Y, and at least one of Z.

Language of degree used herein, such as the terms “approximately,”“about,” “generally,” and “substantially” as used herein represent avalue, amount, or characteristic close to the stated value, amount, orcharacteristic that still performs a desired function or achieves adesired result. For example, the terms “approximately”, “about”,“generally,” and “substantially” may refer to an amount that is withinless than 10% of, within less than 5% of, within less than 1% of, withinless than 0.1% of, and within less than 0.01% of the stated amount. Asanother example, in certain embodiments, the terms “generally parallel”and “substantially parallel” refer to a value, amount, or characteristicthat departs from exactly parallel by less than or equal to 15 degrees,10 degrees, 5 degrees, 3 degrees, 1 degree, or 0.1 degree.

The scope of the present disclosure is not intended to be limited by thespecific disclosures of preferred embodiments in this section orelsewhere in this specification, and may be defined by claims aspresented in this section or elsewhere in this specification or aspresented in the future. The language of the claims is to be interpretedbroadly based on the language employed in the claims and not limited tothe examples described in the present specification or during theprosecution of the application, which examples are to be construed asnon-exclusive.

1. (canceled)
 2. An electric motor assembly, the electric motor assembly comprising: an electric motor having a rotor shaft that extends along a rotor shaft axis of the electric motor, the electric motor being operable to rotate the rotor shaft; a motor frame that houses the electric motor, the rotor shaft protruding from the motor frame; a cooling fan; and a motor drive electronics assembly removably mounted to a non-drive end of the motor frame between the motor frame and the cooling fan, the motor drive electronics assembly having a cavity that houses motor drive electronics, the motor drive electronics assembly further defining a duct that extends, from a inlet formed on an end surface of the motor drive electronics assembly that is distal to the motor frame, to one or more outlets formed on an outer radial wall of the motor drive electronics assembly, wherein, during operation of the cooling fan, air blows on the end surface of the motor drive electronics assembly, and air blows through the duct by entering the inlet and exiting the one or more outlets.
 3. The electric motor assembly of claim 2 wherein at least a portion of the duct extends between the electric motor and the motor drive electronics, radially in a direction perpendicular to an axis of the rotor shaft.
 4. The electric motor assembly of claim 3 wherein a portion of the duct extends circumferentially about the rotor shaft axis.
 5. The electric motor assembly of claim 2 wherein the motor drive electronics assembly removably couples to the rotor shaft at the non-drive end of the motor frame via a rotor shaft bearing.
 6. The electric motor assembly of claim 2 wherein the duct is in fluid communication with the cooling fan via an axial channel defined in the motor drive electronics assembly about the rotor shaft.
 7. The electric motor assembly of claim 2 wherein the cavity is bounded at least in part by a first surface of the motor drive electronics assembly that is proximal to the motor frame and a second surface of the motor drive electronics assembly that opposes the first surface and is distal to the motor frame in relation to the first surface.
 8. The electric motor assembly of claim 7 wherein, during operation of the cooling fan, the cooling fan operates to cool both the first surface and the second surface.
 9. The electric motor assembly of claim 2 wherein the motor drive electronics assembly comprises one or more heat sink fins formed on the end surface.
 10. The electric motor assembly of claim 2 further comprising a shroud cover removably disposable over the motor drive electronics assembly and the cooling fan.
 11. The electric motor assembly of claim 2 wherein the rotor shaft extends through a central opening of the motor drive electronics assembly and the cooling fan is driven by a portion of the rotor shaft that protrudes from the central opening.
 12. A motor drive electronics assembly configured for use with an electric motor, the motor drive electronics assembly comprising: a first end configured to be removably mounted to a non-drive end of a motor frame of an electric motor; a second end opposite the second end and having a cooling duct inlet; an outer radial wall with one or more cooling duct outlets; a cooling fan positioned to blow air on the second end; motor drive electronics within a cavity, the cavity defined at least in part by the outer radial wall; and a cooling duct extending from the cooling duct inlet to the one or more cooling duct outlets, wherein, during operation of the cooling fan, air blows on the second end of the motor drive electronics assembly, and air blows through the cooling duct by entering the cooling duct inlet and exiting the one or more cooling duct outlets.
 13. The motor drive electronics assembly of claim 12 wherein at least a portion of the cooling duct extends between the electric motor and the motor drive electronics, radially in a direction perpendicular to an axis of a rotor shaft of the electric motor.
 14. The motor drive electronics assembly of claim 13 wherein a portion of the cooling duct extends circumferentially about the axis of the rotor shaft.
 15. The motor drive electronics assembly of claim 12 wherein the motor drive electronics assembly removably couples to a rotor shaft of the electric motor at the non-drive end of the motor frame via a rotor shaft bearing.
 16. The motor drive electronics assembly of claim 12 wherein the cooling duct is in fluid communication with the cooling fan via an axial channel defined in the motor drive electronics assembly about a rotor shaft of the electric motor.
 17. The motor drive electronics assembly of claim 12 wherein the cavity is bounded at least in part by a first surface proximal to the first end of the motor drive electronics assembly and a second surface that opposes the first surface and is distal to the first end in relation to the first surface.
 18. The motor drive electronics assembly of claim 17 wherein, during operation of the cooling fan, the cooling fan operates to cool both the first surface and the second surface.
 19. The motor drive electronics assembly of claim 12 wherein the motor drive electronics assembly comprises one or more heat sink fins formed on the second end.
 20. The motor drive electronics assembly of claim 12 further comprising a central opening adapted to receive a rotor shaft of the electric motor, and wherein the cooling fan is configured to be driven by a portion of the rotor shaft that protrudes from the central opening when the motor drive electronics assembly is mounted to the motor frame. 